A Tentative Gamma-Ray Line from Dark Matter Annihilation at the Fermi Large Area Telescope

By Christoph Weniger. 2012

419 citations recorded by the source corpus.

The observation of a gamma-ray line in the cosmic-ray fluxes would be a smoking-gun signature for dark matter annihilation or decay in the Universe. We present an improved search for such signatures in the data of the Fermi Large Area Telescope (LAT), concentrating on energies between 20 and 300 GeV. Besides updating to 43 months of data, we use a new data-driven technique to select optimized target regions depending on the profile of the Galactic dark matter halo. In regions close to the Galactic center, we find a 4.6σ indication for a gamma-ray line at Eγ ≈ 130 GeV. When taking into account the look-elsewhere effect the significance of the observed excess is 3.2σ. If interpreted in terms of dark matter particles annihilating into a photon pair, the observations imply a dark matter mass of mχ = 129.8±2.4 +7−13 GeV and a partial annihilation cross-section of σvχχ → γγ = (1.27±0.32 +0.18−0.28) × 10−27cm3s−1 when using the Einasto dark matter profile. The evidence for the signal is based on about 50 photons; it will take a few years of additional data to clarify its existence.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/9de0f9c03cb48e3e2f26abf8ffef79a6d5d88663

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Citations in the corpus

Search for gamma-ray spectral lines with the Fermi Large Area Telescope and dark matter implications (2013, positive): “Note the R3 significance is comparable to the result reported in [39], where a local significance of ∼ 4.”
WIMP dark matter candidates and searches—current status and future prospects (2017, background): “Another excess in the Fermi-LAT data from the GC was reported in 2012 by [337, 338].”
Gamma Ray Signals from Dark Matter: Concepts, Status and Prospects (2012, background): “confirmation of the signal reported in [13, 14], if systematic uncertainties are sufficiently under control [57]; for CTA, a mere 50 hrs of data might be enough to confirm the signal [314].”
micrOMEGAs4.1: Two dark matter candidates (2014, background): “At the same time several anomalies have been observed in both direct detection [4, 5, 6, 7, 8] and indirect detection experiments [9, 10, 11, 12].”
Double-Disk Dark Matter (2013, background): “These could include observations such as the recently reported Fermi line [3,4], which is challenging to explain without significant boost factors or tuned scenarios (many of which are summarized in [5, 6]).”
Sensitivity projections for dark matter searches with the Fermi large area telescope (2016, methodology): “[57, 241] used somewhat different ROIs that were created by selecting a set of pixels with the largest expected signal-to-noise given the observed data and a similar set of DM density profiles; however the difference in ROIs does not significantly alter the results.”
The Phenomenology of Right Handed Neutrinos (2013, background): “[3] for a review), the annual modulation in the DAMA data [4], the excess of positrons in the cosmic radiation [5, 6], the ”forward-backward asymmetry” observed at the Tevatron [7], the disputed evidence for neutrinoless double β-decay claimed by the Heidelberg-Moscow experiment [8], the cosmologica”
Fermi 130 GeV gamma-ray excess and dark matter annihilation in sub-haloes and in the Galactic centre (2012, methodology): “[4] is showing that regions with optimal size, depending on the assumed DM halo profile, should be used for this type of search.”
Optimized dark matter searches in deep observations of Segue 1 with MAGIC (2013, background): “Also shown is the 〈σannv〉 value corresponding to the 130 GeV gamma-ray line (violet triangle, [64]).”
micrOMEGAs_3: A program for calculating dark matter observables (2013, methodology): “Possible evidence for such lines in FermiLAT data have been reported [10, 11] although the result is not yet confirmed by the FermiLAT collaboration and the DM origin of these lines remains to be established.”